Search Publications
Novel constraints on the particle nature of dark matter from stellar streams
Bovy, Jo; Erkal, Denis; Bertone, Gianfranco +2 more
Tidal streams are highly sensitive to perturbations from passing dark matter (DM) subhalos and thus provide a means of measuring their abundance. In a recent paper, we analyzed the distribution of stars along the GD-1 stream with a combination of data from the Gaia satellite and the Pan-STARRS survey, and we demonstrated that the population of DM …
Exploring the early Universe with Gaia and Theia
Garcia-Bellido, Juan; Murayama, Hitoshi; White, Graham
It has recently been pointed out that Gaia is capable of detecting a stochastic gravitational wave background in the sensitivity band between the frequency of pulsar timing arrays and LISA. We argue that Gaia and Theia have great potential for early universe cosmology, since such a frequency range is ideal for probing phase transitions in asymmetr…
Constraints on a mixed model of dark matter particles and primordial black holes from the galactic 511 keV line
Cai, Rong-Gen; Ding, Yu-Chen; Yang, Xing-Yu +1 more
The galactic 511 keV gamma-ray line has been observed since 1970's, and was identified as the result of electron-positron annihilation, but the origin of such positrons is still not clear. Apart from the astrophysical explanations, the possibilities that such positrons come from dark matter (DM) annihilation are also widely studied. Primordial bla…
Improved treatment of dark matter capture in white dwarfs
Bell, Nicole F.; Ramirez-Quezada, Maura E.; Busoni, Giorgio +2 more
White dwarfs, the most abundant stellar remnants, provide a promising means of probing dark matter interactions, complimentary to terrestrial searches. The scattering of dark matter from stellar constituents leads to gravitational capture, with important observational consequences. In particular, white dwarf heating occurs due to the energy transf…
Dependence of dark matter - electron scattering on the galactic dark matter velocity distribution
Radick, Aria; Taki, Anna-Maria; Yu, Tien-Tien
The rate of dark matter-electron scattering depends on the underlying velocity distribution of the dark matter halo. Importantly, dark matter-electron scattering is particularly sensitive to the high-velocity tail, which differs significantly amongst the various dark matter halo models. In this work, we summarize the leading halo models and discus…
Don't cross the streams: caustics from fuzzy dark matter
Bovy, Jo; Dalal, Neal; Hui, Lam +1 more
We study how tidal streams from globular clusters may be used to constrain the mass of ultra-light dark matter particles, called `fuzzy' dark matter (FDM). A general feature of FDM models is the presence of ubiquitous density fluctuations in bound, virialized dark matter structures, on the scale of the de Broglie wavelength, arising from wave inte…
Magnetars and axion-like particles: probes with the hard X-ray spectrum
Sinha, Kuver; Guo, Huai-Ke; Fortin, Jean-François +2 more
Quiescent hard X-ray and soft gamma-ray emission from neutron stars constitute a promising frontier to explore axion-like-particles (ALPs). ALP production in the core peaks at energies of a few keV to a few hundreds of keV; subsequently, the ALPs escape and convert to photons in the magnetosphere. The emissivity goes as T6 while the con…
Constraining axion-like particles using the white dwarf initial-final mass relation
Dolan, Matthew J.; Hiskens, Frederick J.; Volkas, Raymond R.
Axion-like particles (ALPs), a class of pseudoscalars common to many extensions of the Standard Model, have the capacity to drain energy from the interiors of stars. Consequently, stellar evolution can be used to derive many constraints on ALPs. We study the influence that keV-MeV scale ALPs which interact exclusively with photons can exert on the…
Constraints on MeV dark matter and primordial black holes: Inverse Compton signals at the SKA
Kar, Arpan; Dutta, Bhaskar; Strigari, Louis E.
We investigate the possibilities for probing MeV dark matter (DM) particles and primordial black holes (PBHs) (for masses ~ 1015-1017 g) at the upcoming radio telescope SKA, using photon signals from the Inverse Compton (IC) effect within a galactic halo. Pair-annihilation or decay of MeV DM particles (into e+ e
Testing Primordial Black Holes with multi-band observations of the stochastic gravitational wave background
García-Bellido, Juan; Kuroyanagi, Sachiko; Braglia, Matteo
The mass distribution of Primordial Black Holes (PBHs) is affected by drops in the pressure of the early Universe plasma. For example, events in the standard model of particle physics, such as the W ±/Z 0 decoupling, the quark-hadron transition, the muon and pion becoming non-relativistic, and the annihilation of electrons an…